]. Asthma is one of the most common chronic diseases of childhood. Fortunately, most children with asthma have a mild or moderate form of the disease [1], and symptom control can be achieved by ensuring adequate provision of care and continuously addressing the basics in asthma management through shared decision-making with patients and their families. However, asthma remains difficult to treat for a small proportion of children who may be symptomatic despite aggressive maintenance therapy and after management issues like adherence to treatment have been addressed [2, 3]. The expression "a small proportion" is anecdotal, since estimating the "true" prevalence of severe asthma in childhood has proved challenging. Epidemiological research on this topic is hampered by the heterogeneity in criteria used to define and classify paediatric severe asthma, as well as the scarcity of validated monitoring and outcome-assessment tools [2, 3]. Moreover, even with the adoption of a more standardised and internationally acknowledged definition, an accurate estimate of severe asthma prevalence should be based on very large population cohort studies including information on therapy not only by questionnaires but also from pharmacy-dispensed prescriptions.